Endoglucanases (e.g., endo-beta-1,4-glucanases, EC 3.2.1.4; endo-beta-1,3(1)-glucanases, EC 3.2.1.6; endo-beta-1,3-glucanases, EC 3.2.1.39) hydrolyze internal β-1,4- and/or β-1,3-glucosidic linkages in cellulose and glucan to produce smaller molecular weight glucose and glucose oligomers. Glucans are polysaccharides formed from 1,4β- and/or 1,3-glycoside-linked D-glucopyranose. Endoglucanases are of considerable commercial value, being used in the food industry, for baking and fruit and vegetable processing, breakdown of agricultural waste, in the manufacture of animal feed (e.g., chicken feed), in pulp and paper production, textile manufacture and household and industrial cleaning agents. Endoglucanases are produced by fungi and bacteria.
Beta-glucans are major non-starch polysaccharides of cereals. The glucan content can vary significantly depending on variety and growth conditions. The physicochemical properties of this polysaccharide are such that it gives rise to viscous solutions or even gels under oxidative conditions. In addition glucans have high water-binding capacity. All of these characteristics present problems for several industries including brewing, baking, animal nutrition. In brewing applications, the presence of glucan results in wort filterability and haze formation issues. In baking applications (especially for cookies and crackers), glucans can create sticky doughs that are difficult to machine and reduce biscuit size. In addition, this carbohydrate is implicated in rapid rehydration of the baked product resulting in loss of crispiness and reduced shelf-life. For monogastric animal feed applications with cereal diets, beta-glucan is a contributing factor to viscosity of gut contents and thereby adversely affects the digestibility of the feed and animal growth rate. For ruminant animals, these beta-glucans represent substantial components of fiber intake and more complete digestion of glucans would facilitate higher feed conversion efficiencies. It is desirable for animal feed endoglucanases to be active in the animal stomach.
Endoglucanases are also important for the digestion of cellulose, a beta-1,4-linked glucan found in all plant material. Cellulose is the most abundant polysaccharide in nature. Commercial enzymes that digest cellulose have utility in the pulp and paper industry, in textile manufacture and in household and industrial cleaning agents.
The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the invention is not entitled to antedate such disclosure by virtue of prior invention.